Case stop



Nov. 9, 1965 Filed Sept. 20, 1965 M. J. DE GOOD ETAL CASE STOP 4Sheets-Sheet l @WIM Nov. 9, 1965 M. J. DE GOOD ETAL 3,216,547

CASE STOP Filed Sept. 20, 1965 4 Sheets-Sheet 2 z3 INVENTORS F26 9 MMM/wd .0f may BY zwi www N0v 9, 1965 M. J. DE soon ETAL. 3,216,547

CASE STOP Filed Sept. 20, 1965 4 Sheets-Sheet 3 N0V 9, 1965 M. J. DEGOOD ETAL 3,216,547

CASE STOP 4 Sheets-Sheet 4 Filed Sept. 20, 1963 ZZ Z0 fia.

Fia/4.

INVENTORS www@ J pf @a BY am; 50M/4M Wwf/Vex;

United States Patent O 3,216,547 CASE STOP Maynard J. De Good and CiydeL. Bowman, Grand Rapids, Mich., assignors to The Rapids-StandardCompany, Inc., Grand Rapids, Mich., a corporation of Michigan FiledSept. 20, 1963, Ser. No. 310,393 9 Claims. (Cl. 193-32) This applicationis a continuation-in-part of our copending application, Serial No.98,143, filed March 24, 1961 entitled Case Stop for a Conveyor, nowUnited States Patent No. 3,116,818.

This invention relates to motorized case stops of the type used tointerrupt the ow of articles moving along a conveyor. It is particularlyconcerned with a case stop powered by a constantly operating primemover. The portion of the assembly which makes actual article engagementis connected lto the prime mover by a lost motion or overridingconnection, permitting the prime mover, when desired, to operate withoutmoving the case stop irrespective of whether the stop is extended orretracted.

Case stops of this type must lbe capable of positively arresting themovement of the articles. In so doing, they must be rugged enough towithstand the pressure of the accumulated articles they are holding backand to withstand the impact of the articles when their forward motion isarrested. At the same time, these case stops must effect both positiverelease and positive arrest of the articles.

One of the major disadvantages of the present type of case stops is thatthey do not effect positive arrest of the articles. This is true eventhough the conveyor is equipped with singulation devices (automaticarticle spacing) as shown in U.S. Patent No. 3,062,359. Even withsingulation, it has been found necessary to provide positive stoperection.

This invention is an improvement on the structure shown in applicationSerial No. 98,143. In the present invention, the stop is positivelyerected by the motor. Retraction is initiated by the motor and completedby the weight of the stop itself. It is also an improvement because itis simpler and, therefore, less costly and less bulky. Further, in thisinvention, the prime mover is permitted to operate continuously. Thisgreatly increases the life of the prime mover and eliminates thecircuitry necessary to interrupt its power source. Further, thisstructure eliminates the problem of motor overrun which ischaracteristic of any structure depending upon the stopping and startingof a prime mover.

It is, therefore, an object of this invention to provide a case stopwhich will positively erect the stop and hold it in erected positionwithout interruption of the operation ofthe prime mover.

A further object of this invention is a case stop in which the impact ofarresting the articles and the subsequent pressure exerted by arrestedarticles is not transmitted to the prime mover or the control mechaism.

These and other objects and advantages of this invention will becomemore apparent upon reading the specification in conjunction with theaccompanying drawings.

In the drawings:

FIG. 1 is a fragmentary plan view of a gravity conveyor equipped with acase stop constructed in accordance with the teachings of thisinvention;

FIG. 2 is a schematic, fragmentary side elevation view showing the casestop in erected position;

FIG. 3 is a view similar to FIG. 2 showing the case stop in retractedposition;

FIG. 4 is a plan view of the case stop;

FIGS. 5 and 6 are sectional elevation views taken along the plane V--Vshowing in progressive order the mecha- Nice nism as in passes through anormal operating cycle when prolonged interruption of article ow is notdesired;

FIGS. 7 and 8 are sectional elevation views taken along the same planeas FIGS. 5 and 6 showing in progressive order the mechanism as it passesthrough an operating cycle when prolonged interruption of article flowis desired;

FIG. 9 is a sectional elevation view taken along the plane IX-IX of FIG.4 (omitting the prime mover) showing the mechanism in erected position;

FIG. 10 is a view similar to FIG. 9 showing' the mechanism in retractedposition;

FIG. l1 is a sectional elevation view (omitting the prime mover) takenalong the plane XI-XI of FIG. 4;

FIG. 12 is a sectional elevation view (omitting the prime mover) takenalong the plane XII-XII of FIG. 4;

FIG.-l3 is a fragmentary plan view of this invention applied to aconveyor having a power driven propelling member; and

FIG. 14 is a plan view similar to FIG. 4 but showing the mechanismadapted for the type of conveyor illustrated in FIG. 13.

In executing the purposes of this invention, a conveyor stop is providedhaving a power source which drives a lost motion or override connection.When the lost motion connection is positioned in one attitude, the primemover causes the case stop to become erected. Thereafter, the primemover continues to operate without shifting the stop. When the lostmotion connection is shifted to a second attitude, the stop is shiftedto retracted position and thereafter, the prime mover continues tooperate while the case stop remains retracted. The mechanism includes anover-center toggle which supports and locks the stop in erectedposition. On retraction, the motor unlocks the toggle and thereafter,the weight of the stop completes the retraction movement.

Referring specifically to the drawings, the numeral 10 indicates aconveyor of conventional design having a pair of spaced side rails 11and a plurality of transverse axles 12 connecting the side rails 11.Each of the axles 12 mounts a plurality of conveyor wheels. Thesecollectively form a conveying surface and support the articles beingmoved along the conveyor. Extending between the rails are a pair ofcross braces 14 from which depends the case stop assembly 15.

The case stop 15 has a frame 16 (FIGS. 4, l1 and l2). Seated in theframe is a link member or beam 20. One end of the beam 20 is pivoted at21 to the frame 16. The other end of the beam 20 has a pair ofupstanding fingers 22 which, when erected, project up through theconveying surface and intercept the articles moving along the conveyor(FIG. 2). It will be recognized for the purposes of this invention thatmany different types of structures may be substituted for the fingers22. For instance, a plate may be substituted for theA fingers. The sidesof the fingers may be equipped with conveyor wheels to reduce thefriction incident to contact with the articles as they shift betweenerected and retracted positions. These minor modifications areconventional in the manufacture of case stops and, therefore, are notconsidered to be a part of this invention and further description ofthem is not considered warranted.

R-otatably mounted to the frame is a shaft 23 having a toggle assembly24 secured to it (FIGS. 4 and 9). The lower link 25 of the toggle issecured to the shaft 23 and rocks with it. The upper link 26 of thetoggle is secured to a stud 27 which in turn is attached to the beam 20.The upper end of the lower link 2S is connected to the beam by a tensionspring 28. This spring biases the toggle assembly 24 not only intoerected" position, but over-center to effect a lock supporting the beam20 in erectedv position.

Also secured to the shaft 23 is a lever 30 (FIG. 5 The free end of thelever is equipped with a pin 31. This pin cooperates with an opening 33in the bar 32. The opening 33 consists of an upper slot 34 and a lowerslot 35. These slots communicate through a channel 36 where they overlap(FIG. 6). The pin 31 seats in this opening and may shift from one slotto another by traversing the channel 36. This is the linkage. The bar 32is normally in its lowered position as illustrated in FIGS. and 6. It isbiased into this position by its own weight.

The other end of the bar is pivotally connected at 37a to an eccentric37 which in turn is secured to the shaft 38. The shaft 38 is driven by aprime mover 39 (FIG. 4) through a speed reducer so that the effectivespeed of rotation ofthe shaft 38 is substantially less than that of themotor. The speed reducer is not separately illus trated since it may beincorporated within the housing of the prime mover itself.

Also mounted to the frame 16 is a rock shaft 40 (FIGS. 4 and 5). Securedto the rock shaft is an arm 41 on the free end of which is a cammingrol-ler 42. Also secured to the rock shaft 40 is a strap 43 (FIGS. 4 and11). A spring 45 connects the strap 43 to an actuator 44. The actuator44 may be any suitable piece of equipment such, for example, as asolenoid. A portion of the lower end ,of the bar 32 is notched at 46 toprovidel clearance for the rock shaft 40 (FIG. 5).

The beam 20 is partially biased into erected position by a spring 50(FIGS. 4 and 12). One endl of the spring is secured to the angle 51which in turn is secured to the frame 16 of the case stop 15. The otherend of the spring 50 is attached to a depending foot piece 52 whichitself is rigidly secured to the beam 20. The strength of the spring 50is such that it relieves the prime mover 39 of most of the weight of thebeam 20. However, the spring alone cannot support the beam and thus whenthe prime mover unlocks the toggle, the weight of the beam will shiftthe beam to retracted position.

Operation Considering the beam 20 to be in its down or retractedposition as illustrated in FIG. 5, when the prime mover 39 is energized,the rotation of the shaft 38 will cause the eccentric 37 to reciprocatethe bar 32. As the bar 32 is shifted to the left from the positionillustrated in FIG. 5, the bar 32 will merely slide past the pin 31 andno motion will be transmitted to the pin (FIG. 6).

In this attitude, the stop will remain retracted. When the stop remainsretracted, the cam 42 remains down or inactive. Upon activation of theactuator 44, the cam 42 will be rocked upwardly lifting the bar 32.Should the bar 32 be in a position where the pin 31 prevents upwardmovement of the bar 32 when the cam is rocked, the spring 45 (FIG. 11)will permit the actuator 44 to complete its action even through the cam42 cannot follow. However, as soon as the pin aligns with the channelbetween the slots 34 and 35, the bar 32 will shift and the pin will thenbe seated in the lower slot 35. This will occur when the bar reaches theend of its stroke to the right as illustrated in FIG. 7.

As the bar 32 shifts to the left as illustrated in FIG. 8, the righthand end wall of the lower slot 35 Will push the pin 31 to the left,erecting the toggle (FIG. 9). Thus, the beam 20 is forcibly erected. Asthe toggle 24 nears erection, the spring 28 will shift it over-center,locking the beam 20 in erected position. Thereafter, the bar 32 mayshift to the left without transmitting motion to the pin 31 because ofthe lost motion connection provided by the slot 35.

Because the toggle 24 is in over-center or locked position as shown inFIG. 9, the beam 20 will remain erected even through it is unsupportedby the prime mover 39. The bias of the spring 28 assures the over-centerposition for the toggle.

The beam will remain in erected position until the cam 42 is rockeddown. When this happens, the bar 32 will drop shifting the pin 31 to theupper slot 34. The next shift of the bar 32 to the right will cause theleft hand end wall of the slot 34 to engage the pin, pulling the toggleinto folded position. Once the toggle passes center, the weight of thebeam 20 will cause it to drag. However, should the articles on theconveyor exert such pressure on the lingers 22 as to prevent this, thepositive engagement between the pin and b-ar will assure forcibleretraction by the prime mover. If it is desired to hold the beam 20 inerected position for an extended period, this is accomplished byenergizing the actuator 44. If the beam 20 is to remain retracted, theactuator 44 is de-energized or released.

Control of the actuator 44 may be effected by any suitable means. InFIG. ll, the actuator is shown connected to a power source through apair of conductors 48 one of which is equipped with a switch 49. Thisswitch may be manually operated or alternately it may be responsive toautomatic devices. For example, it may be operated by a sensingmechanism responsive to certain flow con@ ditions along the conveyor orto the availability of conveying space on a conveyor line from whicharticles are received by the conveyor equipped with the case stop. Itmay be responsive totiming devices which limit the movement of articlesto certain predetermined intervals.

For purposes of illustration, the actuator is assumed to be a solenoidwhich when energized retracts the plunger 46. This motion, through thespring 45, rocks the strap 43 to the right, as the structure isillustrated in FIG. ll. This erects the arm 41 bringing the cammingwheel 42 into -contact with the bottom of the bar 32. The upwardmovement of the wheel 42 raises the free end of the bar 32,automatically shifting the pin 31 from the upper slot 34 to the lowerslot 35, as shown in FIGS. 7 and 8. This wheel thus shifts theconnection from one position or ata titude to another. Should thecamming wheel 42 be raised while the bar is in a position where the pincannot shift from one slot to the other, the overriding connectionbetween the solenoid 44 and the strap 46 will permit the plunger of thesolenoid to complete its travel even though the arm 41 cannot completeits movement. The spring 45 will apply sufficient bias to effect upwardmovement of the bar 32 when a point in the cycle is reached whichpermits the pin to shift slots. On retraction, it will be recognizedthat the camming Wheel merely drops away and the bar wil-l drop bygravity when the pin reaches the channel connecting the slots 34 and 35.

When the beam 20 is in its extended or erected position, the linepressure, of the articles piled up against 1t will not be exerted on theprime mover or on lthe pin. This will be absorbed by the shaft or pivot21 and thus transmitted directly to the frame 16. This eliminates alldanger of the prime mover being overloaded by reason of line pressure.Further, it is impossible for the articles to forcibly retract theerected stop, because the toggle 24 having been shifted to or slightlyover-center, as illustrated in FIG. 9, cannot be caused to shift into afolded position, irrespective of the downward pressure applied throughthe fingers 22.

FIGS. 13 and 14 illustrate this linvention applied to a conveyor havinga power driven propelling member. The conveyor 60 is quite similar tothe conveyor illustrated in FIG. 1. The conveyor 60 has a pair of sideframe members 61 joined by axle 62 equipped with conveyor wheels 63.vTraveling through the center of the conveyor is a powered propellingmember or belt 64, the direction of movement of which is indicated bythe arrow in FIG. 13. The case stop 15a is suspended beneath Vtheconveyor by suitable cross lbraces 65. In this construction, the upstanding article engaging ngers 22 straddle the propel ling member, oneon each side.

The case stop 15a is identical to the case stop I5 except that by reasonof the presence of the powereell propelling member 64 the power to`drive the case stole Qau lle.. Clt?- '5 rived from the propellingmember. This eliminates the necessity for the prime mover. This is doneby providing a wheel 66 which engages the return run 64a of thepropelling member 64. The wheel 66 is continuously rotated by thepropelling member and its motion is transmitted to the supporting shaft67. The eccentric 37 is driven by the shaft 68. The motion of the shaft67 is transmitted to the shaft 68 through a Speed reducer 69 to reducethe cycling time of the case stop.

The remainder of the structure of the case stop is identical to the casestop except that some of the operating equipment is shifted slightly toone side to provide adequate space for passage of the return run 64a ofthe propelling member through the frame ofthe case stop. Except that thepower for driving the case stop is desired from the propelling member,the operation of the case stop 15a is identical to the operation of thecase stop 15. The use of this type of a drive mechanism to drive powerfrom a propelling member is the subject of co-pending patentapplication, Serial No. 203,860, iiled I une 20, 1962, now Patent No.3,136,406 entitled Improvement in Operational Controls, whichapplication has a common assignee with this invention.

To reduce line pressure when Ithis case stop is used on a poweredconveyor such as is suggested in FIGS. 13 and 14, a pressure releaseaccumulator type conveyor may be employed. Reference is madeto UnitedStates Patent 3,062,- 359 as illustrating such a conveyor.

It will .be seen that this invention provides a simple case stop havinga minimum number of operating parts. At the same time, it provides apositive stop for the articles. Its structure is such that the powersource, whether it be a prime mover or the return run of the propellingmember, is relieved of providing the energy necessary to resist the linepressure of the articles that are bearing against the stop. Theinvention provides both a positive erection and a positive 'retractionmechanism for the stop fingers. It also permits the prime mover tooperate continuously both when the lingers are erected and when they areretracted.

While there has been shown a preferred embodiment of this inventionytogether with a -modiiication thereof, it will be understood that othermodifications may be constructed incorporating the principles of thisinvention. Such of these modifications as incorporate the principles ofthis invention are to be considered as included in the hereinafterappended claims unless these claims by their language expressly stateotherwise.

We claim:

1. An article stop for a conveyor, said article stop having power drivenmeans and a frame mounting the same; an article interception meansmovable between an erected position and a retracted position; saidarticle interception means being biased into retracted position; amember constantly reciprocated by said power driven means; a shiftableconnection between said member and said article interception means, saidconnection when shifted to one position transmitting said reciprocatingmotion to said article interception means and moving said -articleinterception means to erected position; said connection when so shiftedand said article interception means is in erected position Ibeing a lostmotion connection permitting said member to reciprocate withouttransmission of motion to said article interception means; saidconnection when shifted Ito said other position shifting said articleinterception means from erected to retracted positions; said connectionwhen shifted into said other position and said article interceptionmeans is retracted being a lost motion connection permitting said memberto reciprocate without transmission of motion to said articleinterception means; a movable camming element for holding saidconnection in said one position; a locking element for positivelyholding said article interception means in erected position.

2. An article stop for a conveyor, said article stop having a framemounting a prime mover; a bar secured at one of its ends to andreciprocated by said prime mover; a member pivotally mounted at one ofits ends to said frame, `the other of its ends movable between erectedand retracted positions; said other of said members ends having articleinterception means; a toggle supporting said other end of said member,said toggle when open holding said article interception means inlarticle engaging position and when folded retractng said articleinterception means to inactive position; biasing means urging saidtoggle into over-center locking position when open; a toggle operatinglinkage engaging said bar; means for Vshifting said bar with respect tosaid linkage between a first position and a second position; when saidbar is in said first position said bar in one direction of movementengaging said linkage and shifting said toggle to open position and onopposite movement of said 'ba-rpermitting said bar to move relative tosaid linkage and without transmission of motion to said linkage; saidbar when shifted to said second position connecting said linkage to:said bar and folding said toggle upon movement Iof said bar in 'adirection opposite to that which opened said toggle; said bar when .soshifted and said toggle folded being disconnected from said toggle t-othe extent said bar may reciprocate without transmission of motion tosaid toggle.

3. An article stop for a conveyor, said article stop having a framemounting a prime mover; a bar secured at one of its ends to andreciprocated by said prime mover; a member pivotally mounted at one ofits ends to said frame, the other of its ends movable between erectedand retracted positions; said other of said members ends having articleinterception means; a 'toggle supporting said other end of said member,said toggle when open holding said article interception means in articleengaging position and when folded retracting said article interceptionmeans to inactive position; a toggle operating linkage engaging saidbar; means for shifting the relationship between said bar and saidlinkage between a first position and a second position; when said barand linkage are in said iirst position relative to each other, said barin one direction of movement engaging said linkage and shifting saidtoggle to open position and on opposite movement of said bar permittingsaid bar to return to its original position while said toggle remainsopen; when the relationship between said bar and said linkage is shiftedto said second position said bar engaging said linkage and shifting saidtoggle to folded position as said bar moves in a direction opposite tosaid one direction; on opposite movement of said bar and said bar movingrelative to said linkage without transmission of motion to said linkage.

4. An article stop for a conveyor as described in claim 3 wherein thereis provided resilient means urging said toggle into and over-centerlocking position when open.

S. An article stop for a conveyor as described in claim 2 wherein saidbar has a pair of openings communicating with each other and saidoperating linkage has a pin seated in one of said openings when said baris in said iirst position; said shifting of said bar relocating said pinin the other of said openings.

6. An article stop for a conveyor, said article stop having a framemounting a power driven means; a bar secured at one of its ends to andreciprocated by said power driven means; a link member pivotally mountedat one of its ends to said frame; the other of its ends having articleinterception means; a toggle supporting said other end of said linkmember, said toggle when open holding said article interception means inarticle engaging position and when folded retracting said articleinterception means to inactive position; a toggle operating pin; anopening adjacent thc other of the ends of said bar, said opening beingcharacterized by a pair of laterally offset slots overlapping for aportion of their lengths to form a channel between said slots; said pinbeing received in said opening and normally seated in one of said slots;means for shifting the position of said bar with respect to said pinwhereby said pin is made to seat in the other of said slots; when saidpin is in said one slot said bar in one direction of movement engagingsaid pin and shifting said toggle to folded position and on oppositemovement of said bar said bar sliding past said pin without transmittingany motion to said toggle; when said pin is seated in said other slotsaid bar on movement in said opposite direction engaging said pin andshifting said toggle to open position, said bar on movement in said onedirection sliding past said pin without transmission of motion to saidtoggle; said link member Abeing biased in retracted position.

7. An article stop for a conveyor, said article stop having a framemounting a power driven means; a bar se- 4curedrat one of its ends toand reciprocated by said power driven means; a member pivotally mountedat one of its ends to said frame, the other of its ends being movablebetween erected and retracted positions; said other of said members endshaving article interception means; a toggle supporting said other end ofsaid member, said toggle when open holding said article interceptionmeans in article engaging position and when folded retracting saidarticle interception means to inactive position; a toggle operatinglinkage having a pin; an opening adjacent the other of the ends of saidbar, said opening being characterized by a pair of laterally oiset slotsoverlapping for a portion of their lengths to form a channel betweensaid slots; said pin being received in said opening and normally seatedin one of said slots; means for shifting the position of said bar withrespect to said pin whereby said pin is made to seat in the other ofsaid slots;

' when said pin is in said one slot said bar in one direction ofmovement engaging said pin and shifting said toggle to folded position.and on opposite movement of said bar, said bar sliding past said pinwithout transmission of motion to said toggle; when said pin is seatedin said other slot said bar on movement in said opposite directionengaging said pin and shifting said toggle to open position; said bar onmovement in said one direction sliding past said pin withouttransmission of motion to said toggle; said member being biased intoretracted position.

8. An article stop for a conveyor as described in claim 7 wherein saidtoggle operating linkage has .a shaft rockably mounted on said frame; anarm and one end of said toggle secured to said shaft for simultaneousmovement;

said pin being mounted on said arm; the other end of said toggle beingsecured to said member.

9. An article stop for a conveyor as described in claim 8 wherein saidmeans for shifting said bar has a rock shaft rotatably mounted to saidframe; a lever on one end of said rock shaft, said lever engaging saidbar and upon rocking movement of said rock shaft shifting said bar withrespect to said pin; means for rocking said rock shaft.

References Cited by the Examiner UNITED STATES PATENTS 2,769,520 11/56Davidson et al. 198-26 3,062,359 11/56 McGow et al. 198-160 3,116,8181/64 De Good et al 198-32 3,156,345 11/64 De Good 198-127 3,164,246 1/65De Good 198--100 HUGO O. SCHULZ, Primary Examiner.

SAMUEL F. COLE, Examiner.

1. AN ARTICLE STOP FOR A CONVEYOR, SAID ARTICLE STOP HAVING POWER DRIVENMEANS AND A FRAME MOUNTING THE SAME; AN ARTICLE INTERCEPTION MEANSMOVABLE BETWEEN AN ERECTED POSITION AND A RETRACTED POSITION; SAIDARTICLE INTERCEPTION MEANS BEING BIASED INTO RETRACTED POSITION; AMEMBER CONSTANTLY RECIPROCATED BY SAID POWER DRIVEN MEANS; A SHIFTABLECONNECTION BETWEEN SAID MEMBER AND SAID ARTICLE INTERCEPTION MEANS, SAIDCONNECTION WHEN SHIFTED TO ONE POSITION TRANSMITTING SAID RECIPROCATINGMOTION TO SAID ARTICLE INTERCEPTION MEANS AND MOVING SAID ARTICLEINTERCEPTION MEANS TO ERECTED POSITION; SAID CONNECTION WHEN SO SHIFTEDAND SAID ARTICLE INTERCEPTION MEANS IS IN ERECTED POSITION BEING A LOSTMOTION CONNECTION PERMITTING SAID MEMBER TO RECIPROCATE WITHOUTTRANSMISSION OF MOTION TO SAID ARTICLE INTERCEPTION MEANS; SAIDCONNECTION WHEN SHIFTED TO SAID OTHER POSITION SHIFTING SAID ARTICLEINTERCEPTION MEANS FROM ERECTED TO RETRACTED POSITIONS; SAID CONNECTIONWHEN SHIFTED INTO SAID OTHER POSITION AND SAID ARTICLE INTERCEPTIONMEANS IS RETRACTED BEING A LOST MOTION CONNECTION PERMITTING SAID MEMBERTO RECIPROCATE WITHOUT TRANSMISSION OF MOTION TO SAID ARTICLEINTERCEPTION MEANS; A MOVABLE CAMMING ELEMENT FOR HOLDING SAIDCONNECTION ING SAID ONE POSITION; A LOCKING ELEMENT FOR POSITIVELYHOLDING SAID ARTICLE INTERCEPTION MEANS IN ERECTED POSITION.